Is it fair/possible to get to purple belt level without ever competing?
(edit)
I know it's possible is it fair?

Yes.

It's usually quicker if you compete but still yes. If a guy is young enough and sufficiently injury free then I would recommend competing, if nothing else but to get experience of testing yourself under pressure.

Anyhow. You might as well spit it out. Who in your blue belt opinion got unfairly promoted to purple belt by a highly experience black belt.

genuinely not a troll job, I'm not even a blue belt, but yes it has happened to someone I know (not recently) and I wonder how you can gauge a level if you don't compete or roll with belts of the same level.